Bonding device and bonding method for friction stir bonding and resistance welding

Abstract

A bonding device for joining together a first member (3), an intermediate member (4), and a second member (3) which are layered as a laminated assembly includes a probe (12, 41, 52), an anvil (11), a drive mechanism (14) configured to rotate the probe around the central axial line and move the probe toward and away from the second member along the central axial line, and an electric power supply (15) electrically connected to the anvil and the probe to conduct electric current through the laminated assembly via the anvil and the probe.

1 . A bonding device for joining together a first member, an intermediate member, and a second member which are electroconductive, extend along a prescribed major plane, and are layered in this order as a laminated assembly, comprising:
 an anvil configured to support a first surface of the laminated assembly provided by the first member, and including an electroconductive part abutting against the first surface;   a probe configured to rotate around a central axial line crossing the major plane and move toward and away from a second surface of the laminated assembly provided by the second member at a position corresponding to the anvil, the probe being at least partly electroconductive;   a drive mechanism configured to rotate the probe around the central axial line and move the probe toward and away from the second member along the central axial line;   an electric power supply electrically connected to the anvil and the probe to conduct electric current through the laminated assembly via the anvil and the probe; and   a control unit for controlling operation of the drive mechanism and the electric power supply such that the first member and the intermediate member are joined to each other by resistance welding and the second member and the intermediate member are joined to each other by friction stir bonding.   
     
     
         2 . The bonding device according to  claim 1 , further comprising a shoulder member having a shoulder contact surface configured to be pressed against the second surface, a thorough hole configured to receive the probe, and a recess recessed relative to the shoulder contact surface so as to define a bottom surface opposing the second surface and partly receive the probe. 
     
     
         3 . The bonding device according to  claim 2 , wherein the shoulder member is at least partly electroconductive, and the probe is provided with a probe conductive part extending from a part electrically connected to the power supply to a tip end of the probe opposing the second surface, and a probe insulating part provided on an outer periphery of the probe so as to electrically insulate the probe conductive part from an inner circumferential surface of the through hole. 
     
     
         4 . The bonding device according to  claim 2 , wherein the shoulder member is partly electroconductive, and is provided with a shoulder member insulating part extending over the shoulder contact surface and an inner peripheral surface of the through hole. 
     
     
         5 . The bonding device according to  claim 2 , wherein the friction stir welding is a friction stir spot welding, and the shoulder contact surface has an annular shape centered around the probe. 
     
     
         6 . The bonding device according to  claim 2 , wherein the friction stir welding is a friction stir line welding, and the recess is open in a rear side thereof with respect to a traveling direction of the probe along a welding line. 
     
     
         7 . A bonding method for joining together a first member, an intermediate member, and a second member which are electroconductive, extend along a prescribed major plane, and are layered in this order as a laminated assembly by using the bonding device as defined in  claim 1 , comprising the steps of:
 abutting the anvil against the first surface of the laminated assembly;   pushing the probe into the laminated assembly from the second surface while rotating the probe around the central axial line by using the drive mechanism to join the second member and the intermediate member to each other by friction stir bonding;   as soon as a tip end of the probe reaches the intermediate member, conducting electric current between the probe and the anvil by using the electric power supply to join the first member and the intermediate member to each other by resistance welding; and   pulling the probe away from the laminated assembly.   
     
     
         8 . The bonding method according to  claim 7 , wherein the first member and the intermediate members are made of similar materials, and the second member is made of a material dissimilar from the materials of the first member and the intermediate member, and the materials of the first member and the intermediate member are higher in mechanical strength and electric resistance than the material of the second member. 
     
     
         9 . The bonding method according to  claim 7 , wherein the step of pulling the probe away from the laminated assembly is performed while the probe is kept being rotated around the central axial line.